Rotary engine.



NoI 832,830. PATENTED OCT. 9, 1906.

H. L. WITHAM. ROTARY ENGINE.

APPLIUATION FILED DEO. 22, 1905.

ATTORNEY THE NaRRrs Persks co., wAsHuyaroN, n. c.

HORACE WITHAM, OF LOWELL, MASSACHUSETTS.

ROTARYENGINE.

Specification of Letters Patent.

Patented Oct. 9, 190B.

Application filed December 22, 1905. Serial No. 292,963.

T all whom t may concern:

Be it known that I, HORACE L. WITHAM, a citizen of the United States, residing at Lowell, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Rotary Engines, of which the following is a speciiication.

This invention relates to rotary engines of the type wherein pistons reciprocating within a specially-formed chamber impart a rotary motion to their containing cylinders and therethrough to a driving-shaft.

Engines of a similar type have been devised 'wherein the cylinders and pistons are eccentrically mounted in a cylindrical chamber, against the inside wall of which the outer ends of the pistons bear and cause their cylinders to rotate by reason of the pistons being forced outward -and seeking to reach the outer limit of their strokes.

In this invention the pistons are arranged to reciprocate in directions parallel to and surrounding the driving-shaft, and they impart rotary motion to their cylinders by reason of their ends bearing against end cams, to be described hereinafter, arranged at right angles to the driving-shaft.

l In the drawings accompanying this specification similar characters refer to similar parts in the various views.

Figure 1 is a sectional elevation of my invention, showing only two opposite sets of pistons, the other pistons with their accompanying valve-stems being removed forv clearness of illustration. Fig. 2 is a view similar to Fig. 1, except that iive pistons are shown,

together with a sectional view of the cylinder,

and with the inlet and exhaust valve cases, together with their seats and cams, and the reversing devices removed. Fig. 3 shows in diagrammatic manner the curves of the piston-cams and its relation to the curves ofthe inlet and exhaust valve cams, the respective curves being projected for the purpose. Fig. 4 is a cross-section on the line X X of Fig. 1, except that all pistons, guide-wings, and whirls are shown as in place. Figs. 5 and 8 show opposite ends of the reverse mechanism. Fig. 7 shows an end-view of the inlet-valves and case from the left. Fig. 6 shows a side view of the inlet-valves and case with a section cut out on the line Z Z of Fig., 7. Fig. 9 shows an end viewof the exhaust-valves and case from the right. Fig. 10 shows a side view of the exhaust-valves and case with a section cut out on the line Y Y of Fig. 9. Figs. 6, 7, 9, and 10 are on a larger scale than the others.

In. my invention the casing consists of the tubular or other suitable containing-wall A and the ends B and O, which are fitted thereto with steam-tight joints and held by capscrews 11 or by other suitable means. Cast on the inside of heads B and O or otherwise suitably attached thereto are the end cams D and E. These cams D and E are formed on tubes whose axes coincide with the axis of driving-shaft F by cutting ina double reverse curve, as shown at D in Fig. 3.

The casing A B C is xed to anysuitable foundation by means of ears R or otherwise. Through the casing and bearings 22 22 runs the driving-shaft F. This shaft F (see F ig.1) is axially bored at one end to form the steam-inlet 12. The bore is enlarged at the end to form the bearing-chamber 13. The pierced plug 14 fits snugly chamber 13, so as to allow easy rotation, but to prevent the escape of steam. A ca P is screwed on the end of shaft F and holJds plug 14 in place. Steam is admitted through plug 14, which does not revolve, but permits shaft F to revolve about it.

The cylinder G, which is substantially annular in shape, is keyed, shrunk, or otherwise iirmlyiixed or forced onto shaft F. It is bored lengthwise at equal distances to form a plurality of piston-.chambers 21 21. Referring to Fig. 2, it has also an annular recess 15 to receive inlet-valve case H and an annular recess 16 to receive exhaust-valve case J. It is also provided with passages 17 17, equal in number to the piston-chambers and each of which connects one inlet with one exhaustvalve and with the middle part of one pistonchamber. The annular channel 19 connects 20 2O with annular channel 29 in inlet-valve case H when that is in place.

In each piston-chamber are two pistons 31 41, back to back, so that when steam is admitted between them through the passages 17 17 they are forced outward in opposite directions.

To prevent a set of cylinders from coming together, and lthereby closing the passages 17 17, the ends are somewhat cut away, as shown at 30, besides which there should always be a clearance between the adjoining ends of pistons 31 and 41.

the steam-inlet 12 through suitable passages IIO Each piston is provided with a whirl, as

K K K or L L L, which bears either against F and is provided with gear-teeth 39, Whereby it may be rotated. Side passages 52 52 connect valves 51 51 with passages 17 17. Cam M is ordinarily kept from movement by its connection with the reverse mechanism` to be described. The action of the steam against the heads of these puppetvalves would keep them closed were it not for the action of cam M, which'is so made as to keep two or more always open.

Exhaust-valve case J fits recess 16 in cylinder G and is held in place therein by screws 23 23, which pass through it lengthwise and into cylinder G. The puppet-valves 61 61 are arranged in a circle in case J, each with an independent seat and with an independent exhaust-port 62 62. Each connects with a passage 17. The ends of the stems of these puppet-valves rest upon an end cam N, which fits around shaft F and is similar in other respects to cani M, except in its curved surface, as shown in Fig. 3. It has teeth 40, which mesh with the reverse mechanism and is made to Ikeep at least three valves always open. As valve-cases H and J rotate with cylinder G the stems of their respective puppet-valves travel around cams M and N and are opened and closed in accordance with the curves thereon, as seen Fig. 3.

The reverse mechanism consists of a lever O, which is pivoted by means of a shaft to a projection 49 on the head B. This shaft extends across caseA and bears in a projec- 'tion 59 on head C. Lever O carries a sectional gear 60, which meshes with gear 69. Gear 69 is carried by a short shaft 70, which passes through head B and also carries a gear 71, which meshes with gear-teeth 39 on cam M. Shaft 50 also carries a sectional gear 72, which meshes with gear 73, which should be smaller than 69. Gear 73 is carried by a short shaft 74, which passes through head C and also carries a gear 75, which meshes with gear-teeth 40 on cam N. Lever O has a handle 76 and a reverse gear mechanism 77 of the usual form, whereby it may be released or held in one of three positions against stop 78. Cams M and N can be given a limited rotary movement by means of the lever O through the gears and shafts which connect them, but cam N moves through a greater arc than M by a given motion of lever O on account of the difference in the size of gears 73 and 69.

Figs. 1, 2, 3, 4, 5', and 8 show the position ofthe parts when lever O is at its central position with the engine stopped and at its dead-center. In this position steam is admitted fully through one of the valves 51 and partly through a valve on each side thereof. As the pistons connecting with said middle valve are resting at the highest points of cams D and E, respectively, and as the pistons connecting with the partially-opened valves rest on either side thereof, the pressure is equally balanced and no motion ensues. As the opposite exhaust-valves are open at this point and do not connect with the opened inlet-valves, the steam passes into but not through the engine. Now if the lever O is brought forward enough to cause the raised portions of cams M and N to assume substantially the positions shown by the dotted lines in Fig. 3 valves 51 51 connect with two or more piston-chambers whose pistons 31 41 all bear against the curved surfaces of cams D and E, which have a corresponding slope. Steam thus entering these pistonchambers forces out the contained pistons against the cams D and E, and the outward pressure is converted thereby into a side pressure, whereby cylinder G is revolved, let us say, to the left. This carries along valvecase H, and valves 51 51, by reason of their stems successively passing the high point on cam M, are successively opened and the motion continues. The same movement of lever O brings cam N to such a position (see dotted lines in Fig. 3) that three or more exhaust-valves 61 are opened, thereby permitting the steam from their connecting pistonchambers to exhaust through ports 62 62 at the proper time. This exhaust is assisted by the fact that the cams and valves are so arranged that the exhaust-valves are opened at the limit of stroke of each set of pistons, and from that point the whirls and pistons are pressed back by being forced against the rising portion of the cams D and E, and as their corresponding inlet-valves are closed and their exhaust-valves are open there is nothing to resist such closing action. This rotation to the left thus continues until lever O is brought back to or beyond its dead-center point. When lever O is thus brought back to the dead-center` point, the engine stops, and if brought beyond inlet-valves 51 51, connecting with piston-chambers and pistons on the opposite slope of cams D and E, are opened and brought into action, setting up a revolution of cylinder C and attachments to the right, or, in other words, the engine is reversed. Gear 69 is smaller than 73 to cause the greater throw cf cam N than M, necessitated by the greater length of its raised por-tion.

I prefer when using eight pistons to arrange the raised portion of cam M to cover a curve of about ninety degrees, thus insuring that two or parts of three inlet-valves and v their corresponding pistons will be receiving steam at all times. The reverse mechanism is so arranged that when lever 0 is at the forward point ninety degrees are left for expansion of the inclosed steam.

The raised portion of the cam N covers about one hundred and thirty-five degrees, thus allowing three or parts of four exhaustvalves to be open, whereby their corresponding piston-chambers will be exhausting, and at the forward point of lever O, as described above, through about forty-five degrees, the remaining steam will be compressed. The curves on cams M and N and D and E should be so designed as to avoid any sharp angles or steep grades, as any such would tend to cause the valve-stems and whirls to pound.

To prevent the pistons from swiveling in their chambers, whereby the whirls might not travel at right angles to shaft F, I may use oval or other shaped pistons, any sul table guideways, or, preferably, the guides shown at 81 81, Figs. 1, 2, and 4, These consist of a wing attached to each piston and arranged to project and touch one adjoining piston to the. shape of which it is cut to correspond. These slide 1n and out each with its own piston and each bears enough on an adjoining piston to prevent any swiveling, or I may use flanged instead of plain whirls.

I may use a greater or smaller number of pistons; but l find elght piston-chambers and attachments work very well. A dead-center cannot be caused except by throwing the inlet-valves to the position where an equal number of pistons are taking steam on each side of the high point on cams D and E, and this dead-center can be instantly overcome by moving lever O to the forward or reverse position. j

As each of the two pistons in each of my piston-chambers is forced away from the other by. exactly the same steam-pressure, my engine is perfectly balanced at all times. The steam which enters the engine through plug 14 and inlet 12 should be impregnated with lubricating-oil, and as it passes along through channel 19, passages 20 20, into and through the inlet-valves 51 51, along the passages 52 52 and 17 17` successively into the piston-chambers, back therefrom through passages 17 17, and out through the different exhaust-valves 61 61 and ports 62 62 into the inside of casing A B C it fills up the inside of casing A B C, eventually escaping through exhaust-port 79, it will have come in contact with practically every moving part and will have lubricated it.

It will be understood that my engine may be operated by steam, gas, compressed air, or other expansible fluid and that any number of pistons may be used or other forms of valves and reversing-gears.

What I claim as my invention, and desire t0 cover by Letters Patent, is

1'. In a rotary engine, a casing, a driving- `shaft which passes through said casing and is provided with a longitudinal steam-inlet, two similar end cams oppositely disposed in said casing with axes corresponding to the axis of the driving-shaft, a cylinder carried by the driving-shaft comprising a plurality of longitudinal piston-chambers opposite the end cams and passages connecting the driving-shaft steam-inlet with inlet-valves and a plurality of passages each connecting a piston-chamber with inlet and exhaust valves, a plurality of pistons arranged in sets of two in each piston-chamber, combined with inlet-valves adapted to admit steam successively into the central portions of one or more piston-chambers behind the pistonsthereof, means for operating the inlet-valves, exhaust-valves adapted to exhaust steam successively from the central portion of one or more piston-chambers oppositely disposed from those taking steam, and means for operating said exhaust-valves.

2. In a rotary engine, a casing, a drivingshaft which passes through said casing and is provided with a longitudinal steam-inlet, two similar end cams oppositely disposed in said casing with axes corresponding to the axis of the driving-shaft, a cylinder carried by the driving-shaft comprising a plurality of longitudinal piston-chambers opposite the end cams and passages connecting the driving-shaft steam-inlet with the inlet-valve case and a plurality of passages each connecting a piston-chamber with the inlet and exhaust valves, a plurality of pistons arranged insets of two in each piston-chamber, combined with inlet-valves carried by the cylinder and comprising a case with an annular channel into which protrude the heads of puppet-valves equal in number to the piston-chambers while the valve-stems protrude through the outside of the case, an inlet-valve end cam attached to the casing and adapted to open and close the inlet-valves, exhaust-valves comprising a case carried by the cylinder and puppet-valves equal in number to the piston-chambers with stems which protrude through the outside of the case, and an exhaust-valve end cam att ached to the casing and adapted to open and close the inletvalves.

3. In a rotary engine, a casing, a drivingshaft which passes through said casing and is provided with a longitudinal steam-inlet, two similar end cams oppositely disposed in said casing with axes corresponding to vthe axis of the driving-shaft, a cylinder carried by the driving-shaft comprising a plurality of longitudinal piston-chambers opposite the end cams and passages connecting the driving-shaft steam-inlet with inlet-valves and a plurality of passages connecting the piston- IDO IIO

chambers with inlet and exhaust valves, a plurality of pistons arranged in sets of two in each piston-chamber, combined with inletvalves carried by the cylinder, inlet-valve cams pivoted on the driving-shaft and adapted to open and close the inlet-valves, exhaust-valves carried by the cylinder, exhaust-valve cams pivoted on the drivingshaft and adapted to open and close the exhaust-valves, and reversing mechanism adapted to shift the positions of the inletvalve cams and the exhaust-valve cams with relation to the end cams attached to the cas- In a rotary engine, a casing, a drivingshaft which passes therethrough comprising a longitudinal steam-inlet with an enlarged bore at the end of the shaft, a cylinder and pistons carried by the driving-shaft, cornbined with a pierced cylindrical plug adapted to fit the enlarged bore of the driving-shaft with a running fit and to continue the steaminlet, and a pierced cap screwed to the end of the driving-shaft and adapted to hold the plug in place.

5. In a rotary engine, a casing, end cams oppositely disposed in said casing, a drivingshaft which passes through the casing on the axis of the end cams, a cylinder carried by the driving-shaft and provided with a plurality of longitudinal piston-chambers opposite said cams, a plurality of pistons arranged in sets of two-in each piston-chamber, whirls on the outer ends of said pistons, and a plurality of guide-wings one xed to each of said pistons and adapted to project and conform to the shape of an adjoining piston and to slide thereon, combined with means for admitting steam successively into the central portions of one or more piston-chambers behind the pistons thereof, and means for exhausting the steam successively from the central portion of one or more piston-chambers oppositely disposed therefrom.

6. In a rotary valve, a cylindrical valvecase, an annular inlet in one end thereof, a series of puppet-valves seated in said inlet with stems which project through the opposite end of the valve-case, combined with an end cam adapted by contact with said valvestems to open one or more of said puppetvalves.

In testimony whereof I affix my signature in presence of two witnesses.

l HORACE L. WITHAM.

Witnesses:

HARRY DEMARAs, JOHN KEARNEY. 

